Liquid fuel burning unit of the bowl or pot type



March 4, 1-952 M. RESEK ETAL 2,

LIQUID FUEL BURNING UNIT OF THE. BOWL OR POT TYPE Filed Dec. 1, 1947 3 Sheets-SheeE 1 Q33: ////r 7i 5 III I 74 INVENTOR. Mae: 2555A y Jaw/v 4. flax/157w 147' raxa NE ys March 4, 1952 M. RESEK ET AL LIQU ID FUEL BURNING UNIT OF THE BOWL OR POT TYPE 3 Sheets-Sheet 2 Filed Dec. 1, 1947 STPOM 060.57 8042 INVENTOR. MMC fies-Ex my 4. 04/14 Tale/vs March 4, 1952 M. RESEK ET AL 2,538,045

LIQUID FUEL BURNING UNIT OF THE BOWL OR POT TYPE Filed Dec. 1, 1947 3 Sheets-Sheet 5 Q) 3 0 0 0 g Q E: :2

. INVENTOR. Q Mnec #5554 g R y J/M ,4. 044257 0 *3 406057 8042 mm OMXWW Patented Mar. 4, 1952 UNITED STATES PATENTv OFFICE LIQUID FUEL BURNING UNIT OF THE BOWL OR POT TYPE Application December 1, 1947, Serial No. 789,052

8 Claims.

artifically by a fan or blowerthe subject of our invention is, essentially, a burner of this class.

The type of burner with which our improvements are especially concerned comprises, generally, a burner bowl having perforations in its peripheral wall for the admission of primary air; an annular top wall applied to the peripheral wall and a throat structure surmounting the top wall and including means for admitting secondary air; a housing enclosing -the burner bowl and joined to the throat structure; an air impeller or blower for supplying air to the housing, and means for delivering liquid fuel to the bowl.

Satisfactory performance in burners of the type described is dependent, largely, upon proper control and distribution of the combustion air relative to the quantity and diffusion of the fuel vapors; and prolonged eflicient service depends upon the maintenance of these conditions.

Therefore, it is the primary object of our invention to produce a burner unit including the foregoing parts and wherein said parts are permanently connected together in proper, fixed relation to one another so as to insure against the relationship among the parts becoming disturbed during installation and prolonged use of the unit.

A'ffurther object of the invention is to provide a-sturdy, and relatively light weight burner constifu'ction involving a number of sheet metal parts thatare convenient of assembly and are permane n'tl and relatively immovably joined together, in mostipstances by welding.

A further object of the invention is to improve and strengthen the joint between the top of the burner bowl and the superposed throat structure so as to prevent such joint from parting or becoming loose or cracked due to expansion and contraction of the joined parts, and so as to facilitate fabrication of the unit.

A further object of the invention is to safeguard the top wall of the burner bowl and the throat structure that is joined thereto against deformation or distortion, because a certain relationship between said parts is essential to proper performance, and this is attained by rigid- 1y connecting the burner bowl adjacent the outer edge of its top wall with a part of the throat structure thereabove by means of tie bars that are widely spaced apart circumferentially of the burner bowl and are of such size as not to interfere with a smooth and well distributed supply of secondary air throughout the circumference of the throat structure.

Still further objects of our invention are to eliminate or minimize flame surge or pulsation; to render the fire in the combustion chamber more stable and avoid the tendency of the flame to escape to the flue by the presence of too rich a fuel mixture in the combustion chamber; to obviate adnormal pressure in the combustion chamber due to a momentary back draft condition in the flue; and to produce a substantially uniform flame throughout the bottom area of the combustion chamber, under normal operating conditions, notwithstanding the absence of primary air supply to the burner bowl in the vicinity of the customary lighting and cleanout opening that is sealed during operation by the usual plug.

These last mentioned objects are attained by providing direct, properly restricted, communication between the combustion chamber and the plenum chamber which latter surrounds the burner bowl; by localizing such communication to the general area above the lighting and cleanout opening; and by providing an air director for projecting the air that passes directly from the plenum chamber to the combustion chamber toward the lower central region of the latter.

The objects above enumerated, with others that will appear as this description proceeds, are realized in the construction illustrated in the accompanying drawings wherein similar reference characters designate similar parts throughout the several views.

Fig. 1 is a front elevation of our improved burner unit, with a part of the burner bowl housing broken away and with the plug for the lighting and cleanout opening omitted; Fig. 2 is a central vertical section from front to rear through the burner unit, as indicated by the line 2-2 of Fig. 1, the present view including, in broken lines, the lower portion of the combustion chamber to the bottom wall of which the unit is attached; Fig. 3 is a plan view of the unit, partly in section, such section being in the horizontal plane of the center of the lighting and cleanout opening; Fig. 4 is a detail view, looking forwardly from the line 4-4 of Fig. 3, showing the air director, and Fig. 5 is a perspective view of an air shield employed in theburner unit.

The burner bowl, designated generally by the reference numeral l, comprises an annular top wall 2, a peripheral wall 3 and a bottom wall 4, all made of sheet metal of suitable gauge, that used for the bottom wall being considerably heavier than the metal used for the other walls. In making the peripheral wall 3, a rectangular sheet of metal of the required length and width is pierced to provide air admitting perforations 5, shown as arranged in three circumferential rows that are spaced apart upwardly from about the horizontal central plane of the bowl, and a fourth circumferential row that is near the bottom of the bowl. The sheet of metal is also punched and formed to provide a relatively large lighting and cleanout opening 6, surrounded by a forwardly projecting flange 'l, and the sheet is then formed into a cylinder with its ends slightly overlapped at 8 (Figs. 1 and 3) and connected together by seam welding. The peripheral wall 3 is made convergent at its extreme upper and lower ends by flanging said ends inwardly, as best appears in Fig. 2.

The bottom wall 4 has an upstanding peripheral flange ID that is telescoped over the lower end of the peripheral wall 3 so that the lower convergent end of the peripheral wall bears at its extreme edge against a substantially horizontal annular seat portion II, from which the bottom wall inclines downwardly and inwardly, the inclination becoming more gradual as it approaches the center until it drops off abruptly into a rather shallow saucer-like depression which provides what we shall refer to as the pilot sump l2. The bottom wall 4 has a central hole that is surrounded by a depending flange IS.

The top wall 2 of the burner bowl is shown as having a flat annular seat portion l5 adjacent its outer edge, and a flat annular portion l6 adjacent its inner edge, and between said portions the wall is frusto conical. Outwardly beyond the seat portion l5 the wall is turned downwardly to provide a flange H that is engaged over the upper end of the peripheral wall 3 so that the edge of the convergent top of the peripheral wall is in engagement with the seat portion l5. With the top and bottom walls pressed firmly against the ends of the peripheral Wall 3, the flanges l and I! of the former walls are seam welded to said wall 3. Thus, accuracy in the spacing and disposition of said walls is assured, the convergent ends of the wall 3 providing clearance for the radii between the seat portions l I and I and the respective flanges l0 and I1.

Inwardly of the portion I6, the top wall 2 is extended downwardly and thence inwardly to provide a shallow cylindrical guide wall l8 and a horizontal flange I9. denotes a throat member that is in the form of an annulus and has an inner cylindrical portion 2| that fits within said guide wall I8 and terminates at its lower end in an inwardly directed horizontal flange 22 that seats against, but is considerably narrower than, the flange IS. The inner portion of the latter flange is turned upwardly and thence over and pressed down against the flange '22 to scam lock the throat member 20 to the top wall 2. In this manner the parts are effectively held against separation or relative movement in any direction, as might result, except for this type of connection, from expansion and contraction of said parts. The throat member diverges upwardly from the cylindrical portion 2| to where it joins, through astep 23, a horizontal edge portion 24 that is surrounded by an upstanding flange 25. The cylindrical portion 2| of the throat member, and the adjacent divergent part thereof, are provided with secondary air openings 26 and 21, respectively, of suit- 30 designates a throat extension, which is made able size, number and spacing.

of sheet metal of a considerably heavier gauge than that from which the throat member 20 is 'by an upwardly and outwardly curved flange and provided, inwardly of said flange, with a suitable number of bolt holes 36, shown as rectangular. The overlapping portions of the throat member 20 and the throat extension 30 are secured together, as by welding, and the resultant composite element is referred to herein as the throat structure. A suitable number of tie bars 38 (three, in the present instance) have their lower ends welded to the upper end of the burner 'bowl body, and their upper ends similarly connected to parts of the throat structure there- 'above. These bars are relatively narrow and are spaced at such a distance apart and from the secondary air holes 26 and 21 as not to interfere in any way with an evenly distributed supply of air to all of said holes.

Illustrated by broken lines in Fig. 2 are the peripheral and bottom walls 40 and 4|, respectively, of a combustion chamber C, said bottom wall having, about a large opening therein, a shape complementary to the outer portion of the throat extension 30, such portion embracing the riser 33, step 34 and flange 35. It may be explained that said bottom wall has bolt holes registering with those designated 36 of the throat extension, and bolts 44 are projected downwardly through said holes and have washers and nuts applied to their lower ends to draw the burner unit, of which the throat structure is a part, flrml'y against the underside of the bottom wall 4'! of the combustion chamber.

Engaged upwardly about the riser 33 of the throat extension 30, and permanently and fixedly connected thereto, desirably by seam welding, is the upper end of a cylindrical edge wall of a burner bowl housing, designated generally by the reference numeral 45. A flanged bottom wall 46 is telescoped over the lower end of said edge wall and is fastened to the latter by welding. For this purpose we presently prefer to use that type commonly referred to as are tack welding, and to locate the welds at suitably spaced points about the housing. The bottom wall 46 has a relatively large "central opening that is surrounded by a depending flange 48, and engaged over said opening, and properly located with respect thereto by the flange 48, is a cup-like cover 50 that is surrounded at its upper 'endby a flange 5| that is welded to the bottom wall 46. The peripheral wall of said cover is provided with an opening 52 for the accommodation of a fuel supply conduit 53. The inner end of said conduit is curved upwardly and extended through a hole in the bottom wall 4 of the burner bowl within the area with a leakpro'of joint to said wall. The opening gether.

. burner. of air from the blower against the peripheral wall 52 is enough greater in diameter than the conduit "53 to permit the conduit to be readily engaged through the opening when emplacing the assembled housing about the burner bowl. This differ- -ence in diameter also allows reasonable tolerance in the relation of the conduit to the burner bowl assembly. To close the opening 52 about the conduit 53, a patch 55, having an opening of a size corresponding substantially to the outside diameter of the conduit, is slipped over the conduit and engaged with the cylindrical wall of the thereof with an opening that is in axial alignment with, but is larger than, the lighting and cleanout opening 6 of the burner bowl. Said j opening of the housing is surrounded by a flange 58. Fitting within and projected inwardly through the flange 58 is a sleeve 60 that is reduced in diameter at its inner end to fit within the flange 1 that surrounds the opening 6 of the burner bowl, the latter flange, at its forward end,

being welded to the sleeve. Between the portions of the'sleeve 60 that are of different diameters is a-shoulder against which a gasket 6| seats when a plug 62, by which the gasket is carried, is inserted within the sleeve 60 and turned by means of its handle 63 so that cam portions 54 of the plug underride buttons 55 that are carried by and extend inwardly from the sleeve 68.

A second opening, smaller than that surelbow connection II. This elbow connection is desirably made from two sheet metal shells that have flanges 12 extending from their lateral edges, the flanges of the shells being welded to- The elbow H is of a size and character to have direct connection with, or to receive within its outer end, the outlet nozzle of the snail shell casing of a conventional blower of the class employed extensively in liquid fuel burning apparatus for supplying combustion air to the To prevent impingement of the blast 3 of the burner bowl, and avoid concentration of primary air in this region, a shield 15 is connected, through lugs 18 at its ends, to said wall in spaced relation thereto, so as to permit circulation of air between the shield and wall 3.

Situated centrally of the lower portion of the burner bowl, with its lower end fitting within and welded 0 the flange I3, is an air tube so that, is l' provided near its upper end with diametrically .opposed apertures, one of which, designated 8|, is shown in Fig. 2. Removably applied to the upper end of the air tube is an air head or distributor 82, in the form of a hollow shell that is made up i of sheet metal parts. The bottom of the shell has va central opening surrounded by a flange that fits the adjacent portion of the air tube, while attached to the inner side of the top of the air head or distributor is a sheet metal element providing a locating boss 83 that fits within the top of the tube. The boss is so shaped and located as not to interfere with the passage of air outwardly through the apertures 8|. The air head or distributor is provided with a suitable number of perforations 84 of appropriate size and locationto effect the desired supply and distribution of air within the space enclosed by the pilot to remove "the plug.)

burner wall or skirt 85 that rests on the bottom wall 4 about the sump 12. The wall or skirt 85 is made of sheet metal, and through vertical slots therein are projected sheet metal fins 86 that are radially disposed hooks 88. The wall or skirt 85 is provided with perforations 89 and, about its lower edge, with notches 98.

The space surrounding the burner bowl and "enclosed by the housing 45 and defined at its upper end by the throat structure may be termed a plenum chamber, because of its being supplied with air under pressure by a blower, such space or chamber being designated X in the drawings. Direct communication between this plenum chamber and the combustion chamber C is provided by a port 95, shown as a slot in the interme diate step of the throat extension 30. This port is desirably above that portion of the peripheral wall of the burner bowl that is occupied by the lighting and cleanout opening 6 and therefore devoid of air admitting means when said opening is closed by the plug 62, as is the case at all times when the burner is in operation. Disposed over the port 95.is an air director 96, shown as consisting of an arch-shaped piece of sheet metal, slightly curved lengthwise to conform to the curvature of the throat extension 38. Integral flanges 91 extend from the ends of the director and are spot welded to the underlying portion of the extension 30.

We have explained that the outlet nozzle of a conventional fan or blower is adapted to be connected to the outer end of the elbow H so that such fan or blower will discharge into the plenum chamber X. According to common practice (wherefore it is omitted from the illustration), a source of liquid fuel supply is communicatively connected to the outer end of the conduit 53 through suitable means incorporating a flow control device that is caused to function,v either by manual orautomatic means, to feed a minimum amount of fuel to the sump I2 for pilot fire, and a greater amount for higher fire, and which first mentioned means'limits the maximum supply. .of fuel to the burnerbowl to about the elevation indicated by the broken line a in Fig. 2. Examples of such liquid fuel feeding and control means will be found in the following patents: Nos. 2,214,420, 2,293,697 and 2,295,799, dated, respectively September 10, 1940, August 25, 1942, and September 15, 1942.

When the burner is in operation, say for low or pilot fire, fuel is fed in such volume as to confine the supply to the sump I2. The burner may now be lighted by removing the plug 52 and inserting a suitable lighter through the opening 6, holding it close enough to the oil in the sump 12 (In some cases, an

employed for this purpose, making it unnecessary With the plug replaced, air entering from the plenum chamber X through the tube and air head or distributor 82, as well as through the perforations '5 of the burner bowl 'and thence through the perforations 89 of the wall or skirt 85, will supply the necessary oxygen to support combustion within and above the pilot burner wall or' skirt. The products of combustion, under these circumstances, will rise into the combusion chamber C through the relatively large opening defined by the annularto wall of the burner bowl and the.- throat member In order to produce higher fire, the amount of fuel supplied to the burner bowl is increased, causing the fuel to overflow the sump l2 and, passing through the. notches 9.0. of the wall or skirt 85, to spread over the. adjacent portion. or" the bottom wall of the burner bowl. This. additional fuel will vaporize rapidly under the influence of the heat of the, pilot flame and that given off by the highly heated pilot. burner: parts. and the increased volume of fuel vapors will mix with primary air entering through the. perforations 5 of the burner bowl. As this mixture. rises through the top opening of the burner bowl it will be joined by secondary air entering through the perforations 2S and 21. During higher fire, which term may apply only to intermediate fire, or may embrace both intermediate and high fire, the major volume of combustion occurs in the combustion chamber 0, as will be readily understood.

Usually, while the burner is in operation, the fuel is vaporized at such a rate that there is present in the bottom of the bowl at any one time very little liquid. fuel, the appearance being little more than a dampened condition through- I out the central region of the bottom wall of the bowl. Under these circumstances, and with other conditions favorable, and at higher fire, the flame in the combustion chamber appears to originate within the region of the secondary air F holes of the throat structure and to extend upwardly therefrom a distance depending upon the quantity of fuel that is being fed. However, for a brief period of time attending an increase of the fuel supply, there will be an excess of fuel vapors generated. As a consequence, unless pro visions are made to avoid it, an abnormally rich mixture would rise into the combustion chamber, momentarily deficient in respect to secondary air. Under such circumstances, the existing flame would be. apt to rise high in the combustion chamber, or evento escape to the flue, depriving a subsequent balancedmixture of means or ignition, and creating danger of an explosion. To obviate this condition we provide an auxiliary air supply to the combustion chamber, in the present instance by means of the port 95 in the throat extension 30. Air escaping therethrough is deflected toward the lower central, region of the combustion chamber by the air director Thus, an additional supply of so-called secondary air is injected into the rich mixture rising from the burner bowl, producing a combustible mixture manifested by a name that prevails in the general region of the air director.

By locating the port 95 above theside of the burner bowl occupied by the lighting and cleanout opening 6, which, as will be remembered, is sealed by the plug 62, the supply of auxiliary air is so located as to compensate for the richness of the mixture that rises through the adjacent side of the throat, caused by a deficiency of primary air which, in turn, is due to the absence of perforations 5 in the region of said opening 6. Uniformity of combustion throughout the lower region of the combustion chamber is thus attained.

Direct communication between the combustion chamber C and plenum chamber K through the port 95, also tends toward a better balance of pressure throughout the apparatus andthe elimination, of a pulsating or surging flame that. is characteristic. of the type of combustion apparatus to which the invention pertains; and, by the same token, relief is, provided for abnormal pressure in, the combustion chamber resulting from back drifts in the. flue or chimney.

When it becomes necessary or desirable toiclean or to inspect the pilot burner parts, the plug 62 is removed and, by means of a suitable implement engaged with one or more of the hooks 88, the wall. or skirt 85 may be pried upwardly and removed,v after which the air head or distributor 82 may be lifted from the tube 80.

Having thus described our invention,v what we claim is:

1. In a liquid fuel burner, the combination of a. burner bowl having a top wall provided with a relatively large opening, a throat structure having a similar opening registering with that of said top wall and joined about its inner edge. to the corresponding edge of the top wall, the throat structure being upwardly divergent from its connection with said top. wall and having. a vertical shoulder in substantially vertical alignment. with the periphery of thebowl, a second similar shoulder spaced radially outwardly from the. first mentioned shoulder, a plurality of tie bars having their lower ends rigidly secured to the top peripheral portion of the burner bowl and their upper ends similarly secured to the first mentioned shoulder of the throat structure, adjacent bars being spaced at considerable distance apart circumferentially of the burner bowl, and a burner bowl housing enclosing the burner bowl and having its upper edge engaged with and welded to the second shoulder of the throat structure, the throat structure having circumferential rows of closely spaced air holes adjacent its connection with the top wall of the burner bowl.

2. A liquid fuel burner as defined by claim 1 wherein the throat structure is composed of an inner member of relatively thin sheet metal, and an outer extensionv ofrelatively heavy sheet metal and which includes the aforesaid shoulders, the

adjacent edge portions of said member and extension being overlapped and welded together.

3. A liquid fuel burner comprising a burner bowl having an annular top wall and characterized by a throat structure extending upwardly and outwardly from the inner edge of said top wall, a fuel supply pipe rigidly connected to the bottom of the burner'bowl and extending downwardly and laterally therefrom, a burner bowl housing including a cylindrical wall surrounding said bowl'in spaced substantially concentric relation thereto and having its upper end connected to the throat structure, the housing including, also, a circular bottomv wall that is permanently connected throughout its periphery to the lower end of said cylindrical wall and provided with a substantially central opening, a cup closing said opening and permanently connected about its perimeter to said bottom wall, the side wall of said cup having an aperture substantially greater in diameter than that of the aforesaid fuel supply pipe through which said pipe extends, and a patch of sheet metal having an aperture of substantially the same size as the pipe engaged over the pipe and secured to the side wall of the cup.

4. A liquid fuel burner comprising a burner bowl having an annular top wall and a peripheral wall, the latter wall being provided with a lighting and cleanout opening, a sleeve surrounding said opening and projecting, outwardly from said peripheral wall, an annular throat structure surmounting the burner bowl and secured thereto with its inner edge portion joined to the inner edge portion of the top wall of the burner bowl and provided with means for admitting air to the interior of the said throat structure, a sheet metal housing comprising a peripheral wall enclosing the burner bowl and having its upper end secured to the throat structure, the peripheral wall of the housing being disposed in spaced relation to the corresponding wall of the bowl to provide therebetween a plenum chamber, said wall of the housing being provided with an opening for the aforesaid sleeve, the housing having provision for the supply of air thereto, the throat structure having a port located above the aforesaid sleeve and communicating with said plenum chamber, and an air director surmounting said throat structure above said port and arranged to direct the air issuing through said port substanwall about the opening thereof, the throat structure having air holes closely spaced apart circumferentially thereof in the region of said opening, said structure also being stepped upwardly intermediate its inner and outer edge portions to provide a substantially vertical circumferential shoulder that is of the same diameter as, and is concentric to, the peripheral top portion of the burner bowl, and relatively narrow tie bars spaced a considerable distance apart about the bowl and having their lower ends rigidly connected to the top peripheral portion of the bowl and their upper ends similarly connected to the aforesaid shoulder of the throat structure.

6. A liquid fuel burner unit comprising a burner bowl that is made up of sheet metal parts welded together, said parts including an annular .top wall, an annular throat member above said top wall in vertically spaced relation thereto and having its inner edge portion extended downwardly and non-detachably and relatively immovably secured to the corresponding edge portion of the top wall, said throat member and said top wall being of relatively thin sheet metal, and the latter having circumferential rows of air holes adjacent its connection with said top wall, the outer diameter of said throat member being substantially equal to the corresponding diameter of the top wall, an annular throat extension of relatively heavy sheet metal that is connected about its inner edge by welding to the outer edge portion of the throat member, tie bars spaced a considerable distance apart circumferentially of the burner bowl and having their lower ends welded to the outer edge of the aforesaid top wall and their upper ends similarlyconnected to parts of the throat extension thereabove, and a housing assembly consisting of sheet metal parts that are welded together, said assembly including a cylindrical edge wall that surrounds the burner bowl in spaced relation thereto and has its upper end welded to the throat extension.

7. A liquid fuel burner unit as defined by claim 6 wherein said throat extension projects outwardly beyond the edge wall of the housing where it has provision for fastening means for attaching the burner unit to the bottom wall of a combustion chamber.

8. A liquid fuel burner comprising a burner bowl that includes a sheet metal cylindrical peripheral wall having a shallow convergent portion at its upper end, an annular sheet metal top wall of generally frusto-conical shape having a horizontal seat portion that rests on the top of said peripheral wall and a downwardly directed edge flange that telescopes over the cylindrical portion of said peripheral wall and joins the former horizontal seat portion through a curved part, an annular sheet metal throat member having its inner edge lock seamed to the corresponding edge of said top wall and provided with circumferential rows of closely spaced air holes in the region of its connection with the top wall, the member being cylindrical for a short distance above its connection with the top wall of the burner bowl, and being upwardly divergent therefrom and terminating adjacent its outer edge in a horizontal flange having an upturned edge portion of approximately the same diameter as the edge flange of the foresaid top wall, an annular throat extension constructed of sheet metal considerably heavier than that of the throat member arranged with its inner edge underlying and welded to the horizontal edge portion of the throat member, said extension being stepped upwardly closely adjacent the outer edge of the throat member to provide a circumferential shoulder above the edge flange of the top wall, and thence extending substantially horizontally outwardly and again upwardly and thence outwardly to provide a second circumferential shoulder spaced outwardly from the first mentioned shoullder, a plurality of tie bars having their upper ends welded to the first mentioned shoulder of the throat extension and their lower ends similarly connected to the edge flange of the top wall of the burner bowl, said bars being relatively narrow and spaced a considerable distance apart circumferentially of the burner bowl, and a sheet metal housing enclosing the burner bowl and including a cylindrical peripheral wall arranged with its upper end telescoped over and welded to the second mentioned shoulder of the throat extension.

MARC RESEK JOHN A. DAHLS'IROM.

AUGUST BOLZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

